Chemical and biological sensors are routinely used for homeland defense.
The flexural plate-wave (FPW) sensor is a micromachined, acoustic sensor. FPW sensors function by measuring a change in the velocity of an acoustic wave that is produced by a measurand of interest. The key sensing element in an FPW sensor is a thin “plate” along which ultrasonic flexural waves propagate. Mechanical and material properties of the plate alter the behavior of the sensor by changing the velocity of the propagating wave.
The ability of the FPW sensor to detect minute changes in density, temperature, and pressure, combined with the sensor's capability of operating in liquids or when coated with a gel, make it an interesting candidate as a biosensor.
It is known in the art to employ flexural plate-wave sensors as immunosensor. A FWP immunosensor operates based upon the presence of an antigen. Presence of the antigen is typically determined using standard, solid-substrate assay techniques, similar to ELIZA; however, rather than a radioactive, calorimetric, or fluorescent signal, the FPW is used as a gravimetric sensor for detection. Thus, the amount of protein bound to the solid substrate (the flexing plate of the FPW device) is measured by a change in acoustic wave velocity caused by the added mass of the bound proteins.
Many efforts have been made to extend the use of immunosensors to the identification of analytes. For this purpose, array structures of direct, competitive immunoassays can be used. But the regeneration of immunoarrays is difficult, as the employed antibodies can exhibit different properties. Many different regeneration procedures optimized for single antibodies have been described. This existing procedures require the sensor surface to be reprocessed or use phage to destroy biological molecules, requiring additional fluidic storage with reagents and buffers. A major challenge in field deployment of these FWP immunosensors sensors is the lack of established procedure to regenerate the sensors.
Accordingly, what is needed in the art is an improved regeneration mechanism for immunosensors that does not destroy the primary antibodies in the system.